Trapped vortex combustor for a gas turbine engine with a driver airflow channel

ABSTRACT

A trapped vortex combustor for use in a gas turbine engine includes an outer vortex chamber wall and a dome attached to, or formed integrally with, the outer vortex chamber wall. The dome, the outer vortex chamber wall, or both define at least in part an outer trapped vortex chamber and a channel. The channel extends along the circumferential direction at a forward end of the outer vortex chamber wall, the channel configured to receive an airflow through or around the outer vortex chamber wall, the dome, or both and provide such airflow as a continuous annular airflow to the inner surface of the outer vortex chamber wall. The dome further defines a fuel nozzle opening, with all openings in the dome outward of the fuel nozzle opening along the radial direction, excepting any effusion cooling holes having a diameter less than about 0.035 inches, being in airflow communication with the channel.

FEDERALLY SPONSORED RESEARCH

This invention was made with government support under contract numberN00421-02-C-3202 with the United States Naval Air System Command. Thegovernment may have certain rights in the invention.

FIELD

The present disclosure relates generally to gas turbine engines and,more specifically, to a trapped vortex combustor assembly for use in gasturbine engines.

BACKGROUND

Gas turbine engine are often used to generate thrust for aircraft. Gasturbine engine have a gas path that typically includes, in serial-floworder, an air intake, a compressor section, a combustor, a turbinesection, and a gas outlet. Compressor and turbine sections include atleast one row of circumferentially-spaced rotating blades coupled withina housing. The compressor section generally provides compressed air tothe combustor, where the compressed air is mixed with fuel and combustedto generate combustion gases. The combustion gases flow through theturbine section to power the turbine section. The turbine section may,in turn, power the compressor section and optionally a propulsor, suchas a fan or propeller.

Advanced aircraft gas turbine engine technology requirements are drivingthe combustors therein to be shorter in length, have higher performancelevels over wider operating ranges, and produce lower exhaust pollutantemission levels. Trapped vortex combustors have been developed in anattempt to achieve these goals. As used herein, the term “trapped vortexcombustor” generally refers to a combustor having one or more sections(e.g., inner and/or outer trapped vortex chambers) upstream of acombustion chamber configured to at least partially pre-mix andpre-vaporize a fuel in a swirling vortex of pressurized air.Accordingly, it will be appreciated that with trapped vortex combustors,fuel injectors are typically disposed axially upstream from thecombustion chamber so that the fuel and air has sufficient time to mixand pre-vaporize. In this way, the pre-mixed and pre-vaporized fuel andair mixture may support cleaner combustion thereof in the combustionchamber for reducing exhaust emissions.

However, it is desirable to provide increased pre-mixing andpre-vaporization prior to such mixture reaching the combustion chamber.Accordingly, a trapped vortex combustor capable of providing increasedpre-mixing and/or pre-vaporization would be useful.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one embodiment of the present disclosure, a trapped vortex combustorfor use in a gas turbine engine is provided. The trapped vortexcombustor defines a radial direction and a circumferential direction.The trapped vortex combustor includes an outer vortex chamber walldefining a forward end and including an inner surface. The trappedvortex combustor additionally includes a dome attached to, or formedintegrally with, the outer vortex chamber wall. The dome, the outervortex chamber wall, or both define at least in part an outer trappedvortex chamber and a channel. The channel extends along thecircumferential direction at the forward end of the outer vortex chamberwall, the channel configured to receive an airflow through or around theouter vortex chamber wall, the dome, or both and provide such airflow asa continuous annular airflow to the inner surface of the outer vortexchamber wall. The dome further defines a fuel nozzle opening, with allopenings in the dome outward of the fuel nozzle opening along the radialdirection, excepting any effusion cooling holes having a diameter lessthan about 0.035 inches, being in airflow communication with thechannel.

In certain exemplary embodiments the combustor further includes an innercombustion chamber liner and an outer combustion chamber liner togetherdefining a combustion chamber, wherein the outer vortex chamber ispositioned upstream of the combustion chamber.

In certain exemplary embodiments the dome, the outer vortex chamberwall, or both define a plurality of openings in airflow communicationwith the channel for providing the airflow to the channel. For example,in certain exemplary embodiments both the dome and the outer vortexchamber wall define the plurality of openings. Additionally, forexample, in certain exemplary embodiments the plurality of openings arespaced along the circumferential direction.

In certain exemplary embodiments the outer vortex chamber is configuredto receive a total amount of airflow during operation, and wherein atleast about fifteen percent of the total amount of airflow is providedthrough the channel.

In certain exemplary embodiments the channel extends substantiallycontinuously three hundred and sixty degrees about an axial centerlineof the trapped vortex combustor.

In certain exemplary embodiments the dome includes a lip extending intothe outer vortex chamber, wherein the lip defines the channel with theinner surface of the outer vortex chamber wall.

In certain exemplary embodiments, the trapped vortex combustor furtherincludes a mount, wherein the dome includes a dome flange, wherein theouter vortex chamber wall includes a wall flange, wherein the mountattaches the dome flange to the wall flange, wherein the channel isdefined between the dome flange and the wall flange, and wherein atleast one of the mount, the dome flange, or the wall flange defines aplurality of openings in airflow communication with the channel forproviding the airflow to the channel.

In certain exemplary embodiments the channel is an outer channel, andwherein the combustor further an inner vortex chamber wall defining aforward end and includes an inner surface, wherein the dome is attachedto, or formed integrally with, the inner vortex chamber wall, whereinthe dome, the inner vortex chamber wall, or both define at least in partan inner trapped vortex chamber and an inner channel, the inner channelextending along the circumferential direction at the forward end of theinner vortex chamber wall, the inner channel configured to receive anairflow through or around the inner vortex chamber wall, the dome, orboth and provide such airflow as a continuous annular airflow to theinner surface of the inner vortex chamber wall. For example, in certainexemplary embodiments the fuel nozzle opening of the dome is an outerfuel nozzle opening, wherein the dome further defines an inner fuelnozzle opening, and wherein all openings in the dome inward of the innerfuel nozzle opening along the radial direction, excepting any effusioncooling holes having a diameter less than about 0.035 inches, are inairflow communication with the inner channel. Additionally, for example,in certain exemplary embodiments the inner channel extends substantiallycontinuously three hundred and sixty degrees about an axial centerlineof the trapped vortex combustor.

In certain exemplary embodiments the channel is an outer channeldefining an outlet, wherein the trapped vortex combustor furtherincludes an inner vortex chamber wall defining a forward end, whereinthe dome, the inner vortex chamber wall, or both define at least in partan inner channel at the forward end, wherein the inner channel definesan outlet, wherein the trapped vortex combustor defines a cavity heightbetween the outer vortex chamber wall at the outlet of the outer channeland the inner vortex chamber wall at the outlet of the inner channel,wherein the outer channel further defines a maximum height, and whereinthe maximum height of the outer channel is between about 0.1 percent andabout eight percent of the cavity height.

In certain exemplary embodiments the channel is an outer channeldefining an outlet, wherein the trapped vortex combustor furtherincludes an inner vortex chamber wall defining a forward end, whereinthe dome, the inner vortex chamber wall, or both define at least in partan inner channel at the forward end, wherein the inner channel definesan outlet, wherein the trapped vortex combustor defines a cavity heightbetween the outer vortex chamber wall at the outlet of the outer channeland the inner vortex chamber wall at the outlet of the inner channel,wherein the fuel nozzle opening defines a separation from the innersurface of the outer vortex chamber wall, and wherein the separation isbetween about one percent and about eight percent of the cavity height.

In another exemplary embodiment of the present disclosure, a trappedvortex combustor for a gas turbine engine is provided. The trappedvortex combustor defines a radial direction and a circumferentialdirection. The trapped vortex combustor includes an outer vortex chamberwall defining a forward end and including an inner surface. The trappedvortex combustor additionally includes a dome attached to, or formedintegrally with, the outer vortex chamber wall, the dome, the outervortex chamber wall, or both defining at least in part an outer trappedvortex chamber and a channel, the channel extending along thecircumferential direction at the forward end of the outer vortex chamberwall, the channel configured to receive an airflow through or around theouter vortex chamber wall, the dome, or both and provide such airflow asa continuous annular airflow to the inner surface of the outer vortexchamber wall, wherein the outer vortex chamber is configured to receivea total amount of airflow during operation, and wherein at least aboutfifteen percent of the total amount of airflow is provided through thechannel.

In an exemplary aspect of the present disclosure, a method is providedfor operating a trapped vortex combustor of a gas turbine engine. Thetrapped vortex combustor includes an outer vortex chamber wall and adome attached to, or formed integrally with, the outer vortex chamberwall. The dome, the outer vortex chamber wall, or both defines at leastin part an outer trapped vortex chamber and a channel, the channelpositioned at a forward end of the outer vortex chamber wall. The methodincludes providing an airflow through or around the dome, the outervortex chamber wall, or both to the channel, and providing the airflowreceived in the channel to the outer vortex chamber as an annularairflow, the annual airflow being at least about fifteen percent of atotal amount of airflow provided to the outer vortex chamber.

For example, in certain exemplary aspects the annual airflow is betweenabout twenty percent and about forty percent of the total amount ofairflow provided to the outer vortex chamber.

For example, in certain exemplary aspects providing the airflow throughor around the dome, the outer vortex chamber wall, or both to thechannel includes providing the airflow through a plurality of airflowopenings defined by the dome, the outer vortex chamber wall, or both.

For example, in certain exemplary aspects providing the airflow receivedin the channel to the outer vortex chamber as an annual airflow includesproviding the airflow received in the channel to the outer vortexchamber as an annular airflow along an inner surface of the outer vortexchamber wall.

For example, in certain exemplary aspects the channel is an outerchannel, wherein the combustor further includes an inner vortex chamberwall, wherein the dome is attached to, or formed integrally with, theinner vortex chamber wall, wherein the dome, the inner vortex chamberwall, or both define at least in part an inner trapped vortex chamberand an inner channel positioned at a forward end of the inner vortexchamber wall. With such an exemplary aspect, the method further includesproviding an airflow through or around the dome, the inner vortexchamber wall, or both to the inner channel, and providing the airflowreceived in the inner channel to the inner vortex chamber as an annualairflow, the annual airflow being at least about fifteen percent of atotal amount of airflow provided to the inner vortex chamber.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a schematic, cross-sectional view of a gas turbine engine inaccordance with an exemplary embodiment of the present disclosure.

FIG. 2 is a side, schematic, cross-sectional view of a combustorassembly in accordance with an exemplary embodiment of the presentdisclosure.

FIG. 3 is a side, schematic, cross-sectional view of a combustorassembly in accordance with an exemplary embodiment of the presentdisclosure.

FIG. 4 is a perspective view of a section of the exemplary combustorassembly of FIG. 2.

FIG. 5 is a simplified, schematic view of a forward end of the exemplarycombustor assembly of FIG. 2.

FIG. 6 is a side, schematic, cross-sectional view of a combustorassembly in accordance with another exemplary embodiment of the presentdisclosure.

FIG. 7 is a side, schematic, cross-sectional view of a combustorassembly in accordance with yet another exemplary embodiment of thepresent disclosure.

FIG. 8 is a flow diagram of a method of operating a trapped vortexcombustor of a gas turbine engine in accordance with an exemplaryembodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to present embodiments of theinvention, one or more examples of which are illustrated in theaccompanying drawings. The detailed description uses numerical andletter designations to refer to features in the drawings. Like orsimilar designations in the drawings and description have been used torefer to like or similar parts of the invention.

As used herein, the terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terms “forward” and “aft” refer to relative positions within a gasturbine engine or vehicle, and refer to the normal operational attitudeof the gas turbine engine or vehicle. For example, with regard to a gasturbine engine, forward refers to a position closer to an engine inletand aft refers to a position closer to an engine nozzle or exhaust.

The terms “upstream” and “downstream” refer to the relative directionwith respect to fluid flow in a fluid pathway. For example, “upstream”refers to the direction from which the fluid flows, and “downstream”refers to the direction to which the fluid flows.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise.

Approximating language, as used herein throughout the specification andclaims, is applied to modify any quantitative representation that couldpermissibly vary without resulting in a change in the basic function towhich it is related. Accordingly, a value modified by a term or terms,such as “about”, “approximately”, and “substantially”, are not to belimited to the precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value, or the precision of the methods or machines forconstructing or manufacturing the components and/or systems. Forexample, the approximating language may refer to being within a tenpercent margin.

Here and throughout the specification and claims, range limitations arecombined and interchanged, such ranges are identified and include allthe sub-ranges contained therein unless context or language indicatesotherwise. For example, all ranges disclosed herein are inclusive of theendpoints, and the endpoints are independently combinable with eachother.

Referring now to the drawings, wherein identical numerals indicate thesame elements throughout the figures, FIG. 1 is a schematiccross-sectional view of a gas turbine engine in accordance with anexemplary embodiment of the present disclosure. More particularly, forthe embodiment of FIG. 1, the gas turbine engine is a high-bypassturbofan jet engine 10, referred to herein as “turbofan engine 10.” Asshown in FIG. 1, the turbofan engine 10 defines an axial direction A(extending parallel to a longitudinal centerline 12 provided forreference), a radial direction R, and a circumferential direction (i.e.,a direction extending about the axial direction A; not depicted). Ingeneral, the turbofan 10 includes a fan section 14 and a core turbineengine 16 disposed downstream from the fan section 14.

The exemplary core turbine engine 16 depicted generally includes asubstantially tubular outer casing 18 that defines an annular inlet 20.The outer casing 18 encases, in serial flow relationship, a compressorsection including a booster or low pressure (LP) compressor 22 and ahigh pressure (HP) compressor 24; a combustion section 26; a turbinesection including a high pressure (HP) turbine 28 and a low pressure(LP) turbine 30; and a jet exhaust nozzle section 32. A high pressure(HP) shaft or spool 34 drivingly connects the HP turbine 28 to the HPcompressor 24. A low pressure (LP) shaft or spool 36 drivingly connectsthe LP turbine 30 to the LP compressor 22.

For the embodiment depicted, the fan section 14 includes a variablepitch fan 38 having a plurality of fan blades 40 coupled to a disk 42 ina spaced apart manner. As depicted, the fan blades 40 extend outwardlyfrom disk 42 generally along the radial direction R. Each fan blade 40is rotatable relative to the disk 42 about a pitch axis P by virtue ofthe fan blades 40 being operatively coupled to a suitable actuationmember 44 configured to collectively vary the pitch of the fan blades 40in unison. The fan blades 40, disk 42, and actuation member 44 aretogether rotatable about the longitudinal axis 12 by LP shaft 36 acrossa power gear box 46. The power gear box 46 includes a plurality of gearsfor stepping down the rotational speed of the LP shaft 36 to a moreefficient rotational fan speed.

Referring still to the exemplary embodiment of FIG. 1, the disk 42 iscovered by rotatable front nacelle 48 aerodynamically contoured topromote an airflow through the plurality of fan blades 40. Additionally,the exemplary fan section 14 includes an annular fan casing or outernacelle 50 that circumferentially surrounds the fan 38 and/or at least aportion of the core turbine engine 16. It should be appreciated that thenacelle 50 may be configured to be supported relative to the coreturbine engine 16 by a plurality of circumferentially-spaced outletguide vanes 52. Moreover, a downstream section 54 of the nacelle 50 mayextend over an outer portion of the core turbine engine 16 so as todefine a bypass airflow passage 56 therebetween.

During operation of the turbofan engine 10, a volume of air 58 entersthe turbofan 10 through an associated inlet 60 of the nacelle 50 and/orfan section 14. As the volume of air 58 passes across the fan blades 40,a first portion of the air 58 as indicated by arrows 62 is directed orrouted into the bypass airflow passage 56 and a second portion of theair 58 as indicated by arrow 64 is directed or routed into the LPcompressor 22. The ratio between the first portion of air 62 and thesecond portion of air 64 is commonly known as a bypass ratio. Thepressure of the second portion of air 64 is then increased as it isrouted through the high pressure (HP) compressor 24 and into thecombustion section 26, where it is mixed with fuel and burned to providecombustion gases 66. Notably, as will be described in greater detail,below, the combustion section 26 includes a trapped vortex combustor formixing the compressed air with fuel and generating combustion gases 66.

The combustion gases 66 are routed through the HP turbine 28 where aportion of thermal and/or kinetic energy from the combustion gases 66 isextracted via sequential stages of HP turbine stator vanes 68 that arecoupled to the outer casing 18 and HP turbine rotor blades 70 that arecoupled to the HP shaft or spool 34, thus causing the HP shaft or spool34 to rotate, thereby supporting operation of the HP compressor 24. Thecombustion gases 66 are then routed through the LP turbine 30 where asecond portion of thermal and kinetic energy is extracted from thecombustion gases 66 via sequential stages of LP turbine stator vanes 72that are coupled to the outer casing 18 and LP turbine rotor blades 74that are coupled to the LP shaft or spool 36, thus causing the LP shaftor spool 36 to rotate, thereby supporting operation of the LP compressor22 and/or rotation of the fan 38.

The combustion gases 66 are subsequently routed through the jet exhaustnozzle section 32 of the core turbine engine 16 to provide propulsivethrust. Simultaneously, the pressure of the first portion of air 62 issubstantially increased as the first portion of air 62 is routed throughthe bypass airflow passage 56 before it is exhausted from a fan nozzleexhaust section 76 of the turbofan 10, also providing propulsive thrust.The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section32 at least partially define a hot gas path 78 for routing thecombustion gases 66 through the core turbine engine 16.

It should be appreciated, however, that the exemplary turbofan engine 10depicted in FIG. 1 is by way of example only, and that in otherexemplary embodiments, the turbofan engine 10 may have any othersuitable configuration. For example, in other exemplary embodiments, theturbofan engine 10 may instead be configured as, e.g., a direct-driveturbofan engine, a fixed-pitch turbofan engine, etc. Additionally, oralternatively, the turbofan engine 10 may be configured as a turbopropengine, a turbojet engine, a turboshaft engine, a ramjet engine, anauxiliary power unit engine, etc. Additionally, or alternatively, still,in other embodiments the turbofan engine 10 of FIG. 1 may instead beconfigured as an aeroderivative gas turbine engine, e.g., for nauticaluses, or as an industrial gas turbine engine, e.g., for powergeneration.

Referring now to FIG. 2, a close-up, cross-sectional view of acombustion section 26 of a gas turbine engine in accordance with anexemplary embodiment of the present disclosure is provided. Thecombustion section 26 depicted in FIG. 2 may, in certain exemplaryembodiments, be the exemplary combustion section 26 described above withreference to FIG. 1. However, in other exemplary embodiments, thecombustion section 26 of FIG. 2 may be incorporated into any othersuitable gas turbine engine, such as any suitable turboprop engine,turbojet engine, turboshaft engine, ramjet engine, auxiliary power unitengine, aeroderivative gas turbine engine, industrial gas turbineengine, etc.

As will be appreciated, the combustion section 26 generally includes acombustor 100, with the combustor 100 defining an axial direction A (andan axial centerline 102; see FIG. 5), a radial direction R, and acircumferential direction C (i.e., a direction extending about the axialdirection A; see FIG. 3). Notably, in certain exemplary embodiments, theaxial direction A, radial direction R, and circumferential direction Cdefined by the combustor 100 may align with the axial direction A,radial direction R, and circumferential direction C defined by the gasturbine engine within which it is installed (see FIG. 1), and further,the axial centerline 102 may align with the longitudinal centerline 12of the gas turbine engine within which it is installed (see FIG. 1).

The exemplary combustor 100 depicted in FIG. 2 is generally configuredas, and referred to herein as, a trapped vortex combustor 100. Thetrapped vortex combustor 100 generally includes a dome 104, an outervortex chamber wall 106, and an inner vortex chamber wall 108. The outervortex chamber wall 106 extends between and defines a forward end 110and an aft end 112, and similarly, the inner vortex chamber wall 108extends between and defines a forward end 114 and an aft end 116. Thedome 104 is attached to, or formed integrally with, the outer vortexchamber wall 106 at the forward end 110 of the outer vortex chamber wall106, and further is attached to or formed integrally with, the innervortex chamber wall 108 at the forward end 114 of the inner vortexchamber wall 108. The dome 104, the outer vortex chamber wall 106, orboth define, at least in part, an outer trapped vortex chamber 118, andfurther the dome 104, the inner vortex chamber wall 108, or both defineat least in part an inner trapped vortex chamber 120.

The trapped vortex combustor 100 further includes an outer transitionwall 122 and an inner transition wall 124. The outer transition wall 122is attached to, or formed integrally with, the outer vortex chamber wall106 at the aft end 112 of the outer vortex chamber wall 106, and extendsgenerally inwardly along the radial direction R to further define theouter trapped vortex chamber 118. The inner transition wall 124 issimilarly attached to, or formed integrally with, the inner vortexchamber wall 108 at the aft end 116 of the inner vortex chamber wall108, and extends generally outwardly along the radial direction R tofurther define the inner trapped vortex chamber 120.

Further, the trapped vortex combustor 100 includes an outer combustionchamber liner 126 and an inner combustion chamber liner 128. The outercombustion chamber liner 126 is attached to, or formed integrally with,the outer transition wall 122 and extends generally aft therefrom.Similarly, the inner combustion chamber liner 128 is attached to, orformed integrally with, the inner transition wall 124 and also extendsgenerally aft therefrom. For the embodiment depicted, the innercombustion chamber liner 128 and outer combustion chamber liner 126together define at least in part a combustion chamber 130. The outertrapped vortex chamber 118 is positioned forward of, and upstream of,the combustion chamber 130, and the inner trapped vortex chamber 120 issimilarly positioned forward of, and upstream of, the combustion chamber130.

Referring still to FIG. 2, the trapped vortex combustor 100 furtherincludes a fuel nozzle assembly 132. The fuel nozzle assembly 132generally includes a plurality of fuel nozzles configured to providefuel to the outer trapped vortex chamber 118 and to the inner trappedvortex chamber 120 during operation. Additionally, the dome 104generally defines a plurality of fuel nozzle openings configured toreceive the respective plurality of fuel nozzles of the fuel nozzleassembly 132. More particularly, for the embodiment depicted, the dome104 defines an outer fuel nozzle opening 134 and an inner fuel nozzleopening 136. The outer fuel nozzle opening 134 is configured to receivea corresponding outer fuel nozzle 138, which is configured to providefuel to the outer trapped vortex chamber 118. The inner fuel nozzleopening 136 is configured to receive a corresponding inner fuel nozzle140, which is configured to provide fuel to the inner trapped vortexchamber 120. It will be appreciated that although for the embodimentdepicted the inner and outer fuel nozzles 140, 138 are positioned inopenings 136, 134, respectively, in the dome 104, in other exemplaryaspects of the present disclosure, the fuel nozzles 140, 138 may insteadbe positioned in openings defined in the inner vortex chamber wall 108and outer vortex chamber wall 106, respectively, or at any othersuitable location.

Moreover, the trapped vortex combustor 100 is configured to provide anairflow to the inner and outer trapped vortex chambers 120, 118 to mixwith the fuel provided thereto and to generate combustion gases 66. Moreparticularly, for the embodiment depicted, the dome 104, the outervortex chamber wall 106, or both define at least in part an outerchannel 142 extending along the circumferential direction C at theforward end 110 of the outer vortex chamber wall 106. Additionally, thedome 104, the inner vortex chamber wall 108, or both define at least inpart an inner channel 144 similarly extending along the circumferentialdirection C at the forward end 114 of the inner vortex chamber wall 108.Notably, the outer vortex chamber wall 106 defines an inner surface 146and the inner vortex chamber wall 108 similarly defines an inner surface148. The outer channel 142 is configured to receive an airflow throughor around the outer vortex chamber wall 106, the dome 104, or both andprovide such airflow as a continuous annular airflow to the innersurface 146 of the outer vortex chamber wall 106. Additionally, theinner channel 144 is configured to receive an airflow through or aroundthe inner vortex chamber wall 108, the dome 104, or both and providesuch airflow as a continuous annular airflow to the inner surface 148 ofthe inner vortex chamber wall 108. It will be appreciated, that as usedherein, the description “at the forward end” with respect to thelocation of the outer channel 142 and/or inner channel 144 refers to thechannel being defined at least in part within a forward ten percent ofthe outer vortex chamber wall 106 or inner vortex chamber wall 108,based on an entire length of the respective wall.

Referring still to FIG. 2, and now also to FIG. 3, providing a close-upview of the outer trapped vortex chamber 118, the outer trapped vortexchamber 118 will be described in greater detail. As is depicted, for theembodiment of FIGS. 2 and 3, the dome 104 and the outer vortex chamberwall 106 together define the outer channel 142 at the forward end 110 ofthe outer vortex chamber wall 106. More specifically, the dome 104includes a lip 150 extending into the outer trapped vortex chamber 118in a direction generally perpendicular to a forward wall of the dome104, with the lip 150 defining the outer channel 142 with the innersurface 146 of the outer vortex chamber wall 106. Notably, however, inother exemplary embodiments, the lip 150 may not be required, andinstead a portion of the dome 104 and/or the outer trapped vortexchamber wall 106 may be extended to define the outer channel 142.

Additionally, as will be described in greater detail below, the dome104, the outer vortex chamber wall 106, or both define a plurality ofouter openings 152 in airflow communication with the outer channel 142for providing the airflow to the outer channel 142. More particularly,for the embodiment depicted, the outer channel 142 defines an outlet 154and each of the plurality of outer openings 152 defined by the dome 104,the outer trapped vortex chamber 118, or both are directly in airflowcommunication with the outer channel 142 at a location upstream of theoutlet 154 of the outer channel 142.

It should be appreciated, that the airflow provided to and through theouter channel 142 is a substantial portion of a total amount of airflowprovided to the outer trapped vortex chamber 118 during operation, andthus may be considered a driver airflow (i.e., driving the vortex ofair, described below). However, as is depicted in FIG. 3, the trappedvortex combustor 100 further includes additional airflow sources for theouter trapped vortex chamber 118. For example, the outer vortex chamberwall 106 further includes a second airflow source 156 at the aft end 112of the outer vortex chamber wall 106, the outer transition wall 122includes a third airflow source 158 at an inner end of the outertransition wall 122, and the dome 104 includes a fourth airflow source160 inward of the outer fuel nozzle opening 134 along the radialdirection R. For the embodiment depicted, the second airflow source 156is similarly configured as a channel configured receive an airflowthrough an opening 162 defined by the outer vortex chamber wall 106 atthe aft end 112 of the outer vortex chamber wall 106 leading to thechannel. Similarly, the third airflow source 158 is also configured as achannel configured receive an airflow through an opening 164 defined bythe outer transition wall 122 at the radially inner end of the outertransition wall 122 leading to the channel. By contrast, however, thefourth airflow source 160 is simply configured as an opening in the dome104.

Accordingly, it will be appreciated that during operation of the trappedvortex combustor 100, the airflow provided through the plurality ofairflow sources (the airflow generally labeled as numeral 165), alsoreferred to air driver jets, discussed below, generates a trapped vortexof air and fuel mixture 166, ignited to generate the combustion gases66. Additionally, during operation of the trapped vortex combustor 100,the outer trapped vortex chamber 118 is configured receive a totalamount of airflow from all of the plurality of airflow sources combined.As stated, the airflow provided to and through the outer channel 142,however, is a substantial portion of the total amount of airflowprovided to the outer trapped vortex chamber 118 during operation. Forexample, in certain exemplary embodiments, at least about fifteenpercent of the total amount of airflow is provided through the outerchannel 142, such as at least about twenty percent, such as at leastabout twenty-five percent, such as up to about forty percent.

Moreover, as is also depicted in FIG. 3 the outer channel 142 furtherdefines a maximum height 168 at a location upstream of the outlet 154 ofthe outer channel 142. The maximum height 168 is defined in a directionparallel to a forward wall of the dome 104 in the plane depicted in FIG.3 (i.e., a plane defined by the axial direction A and the radialdirection R). Further, the outer fuel nozzle opening 134 defines aseparation 170 from the inner surface 146 of the outer vortex chamberwall 106 (i.e., a minimum separation). The separation 170 is similarlydefined in a direction parallel to the forward wall of the dome 104 inthe plane depicted in FIG. 3. As will be appreciated, providing driverairflow through the outer channel 142 allows for the outer fuel nozzleopening 134 to be moved outwardly generally along the radial directionR. More specifically, by sizing the outer channel 142 to provide adesired amount of airflow allows for all of a forward driver airflowprovided to the outer trapped vortex chamber 118 at a radially outer andforward zone to be provided through the outer channel 142, allowing forthe separation 170 to be reduced, i.e., allowing the outer fuel nozzle138 to be moved outward along the radial direction R. Such may lead toan increase in efficiency of the trapped vortex combustor 100.Accordingly, as is depicted, all openings (which may be no openings insome embodiments) in the dome 104 outward of the outer fuel nozzleopening 134 along the radial direction R are in airflow communicationwith the outer channel 142, with the exception of potential effusioncooling holes. Any of these effusion cooling holes, if included, wouldhave a diameter less than about 0.035 inches, such as less than about0.030 inches, such that they would be unable to substantially contributeto the forward driver airflow provided through the outer channel 142.

Further, referring back briefly to FIG. 2, it will be appreciated thatthe trapped vortex combustor 100 defines a cavity height 172 between theouter vortex chamber wall 106 at the outlet 154 of the outer channel 142and the inner vortex chamber wall 108 at an outlet of the inner channel144. For the embodiment depicted, the maximum height 168 of the outerchannel 142 is between about 0.1 percent and about eight percent of thecavity height 172, and further, the separation 170 of the outer fuelnozzle opening 134 with the inner surface 146 of the outer vortexchamber wall 106 is between about one percent and about eight percent ofthe cavity height 172. For example, in certain exemplary embodiments,the maximum height 168 of the outer channel 142 may be at least about0.2 percent of the cavity height 172, such as at least about 0.3 percentof the cavity height 172, such as at least about two percent of thecavity height 172, such as up to about seven percent of the cavityheight 172, such as up to about six percent of the cavity height 172.

Notably, it should be appreciated that for the embodiment depicted, theinner trapped vortex chamber 120 is configured in substantially the samemanner as the outer trapped vortex chamber 118, only mirrored. Forexample, for the embodiment depicted, the inner trapped vortex chamber120 also includes a second airflow source 174, a third airflow source176, and a fourth airflow source 178. Additionally, the inner channel144 may be configured to provide at least about fifteen percent of atotal amount of airflow to the inner trapped vortex chamber 120 duringoperation, such as at least about twenty percent, such as at least abouttwenty-five percent, such as up to about forty percent. Further, theinner channel 144 may have similar dimensions as the outer channel 142(e.g., the maximum height), and the inner fuel nozzle opening 136 maydefine a similar separation with the inner surface 148 of the innervortex chamber wall 108. Moreover, as will be discussed in greaterdetail below, the dome 104, the inner vortex chamber wall 108, or bothdefine a plurality of inner openings 180 in airflow communication withthe inner channel 144 for providing the airflow to the inner channel144.

Referring now also to FIG. 4, a perspective, cross-sectional view of aforward end 110 of the exemplary trapped vortex combustor 100 of FIGS. 2and 3 is provided. As briefly stated above, the dome 104, the outervortex chamber wall 106, or both define a plurality of outer openings152 in airflow communication with the outer channel 142 for providingthe airflow to the outer channel 142. Additionally, the dome 104, theinner vortex chamber wall 108, or both define a plurality of inneropenings 180 in airflow communication with the inner channel 144 forproviding airflow to the inner channel 144. For the embodiment depicted,both the dome 104 and the outer vortex chamber wall 106 define theplurality of outer openings 152, and similarly both the dome 104 and theinner vortex chamber wall 108 define the plurality of inner openings180. Additionally, the plurality of outer openings 152 are spacedsubstantially evenly along the circumferential direction C of thetrapped vortex combustor 100, and the plurality of inner openings 180are similarly spaced substantially evenly along the circumferentialdirection C of the trapped vortex combustor 100. However, in otherexemplary embodiments, the plurality of outer openings 152 and/or theplurality of inner openings 180 may instead define any other suitablespacing.

Notably, it will further be appreciated that in addition to the outerfuel nozzle opening 134 and inner fuel nozzle opening 136 describedabove with reference to FIG. 2, the dome 104 further defines a pluralityof outer fuel nozzle openings 134 spaced substantially evenly along thecircumferential direction C, as well as a plurality of inner fuel nozzleopenings 136 spaced substantially evenly along the circumferentialdirection C. Each of the outer fuel nozzle openings 134 may beconfigured to receive a respective outer fuel nozzle 138 of the fuelnozzle assembly 132 and each of the inner fuel nozzle openings 136 maybe configured to receive a respective inner fuel nozzle 140 of the fuelnozzle assembly 132.

Moreover, it will be appreciated that for the embodiment depicted, theouter channel 142 extends substantially continuously three hundred sixtydegrees about the axial centerline 102 of the trapped vortex combustor100 and similarly, the inner channel 144 also extends substantiallycontinuously three hundred sixty degrees about the axial centerline 102of the trapped vortex combustor 100. For example, referring briefly toFIG. 5, a simplified, schematic view of a forward end of the exemplarytrapped vortex combustor 100 of FIGS. 2 through 4 is provided. As isdepicted schematically, and in phantom, the outer channel 142 extendssubstantially continuously three hundred sixty degrees about the axialcenterline 102 of the trapped vortex combustor 100 and similarly, theinner channel 144 also extends substantially continuously the inner and60 degrees about the axial centerline 102 of the trapped vortexcombustor 100. Notably, as used herein, extending “substantiallycontinuously” with reference to one or both of the outer channel 142 orinner channel 144 refers the respective channel extending along thecircumferential direction C with less than ten percent of an entireannular volume being blocked by, e.g., connection walls, struts, etc.For example, although the dome 104 and outer vortex chamber wall 106 aredepicted as each being single, monolithic components extendingcontinuous three hundred and sixty degrees about the axial centerline102, in other embodiments, one or both of these components may be formedof separate components joined in any suitable manner (e.g., may includeattachment members that block small portions of one or both of the outeror inner channels 142, 144, such as less than ten percent by totalannular volume of the respective channel).

Referring back to FIG. 4, as briefly stated above, providing the abovedisclosed amounts of airflow through the outer channel 142 may allow formoving the outer fuel nozzle openings 134 outwardly generally along theradial direction R as no other airflow nozzles are required in the dome104 to provide sufficient driver airflow. Accordingly, all the openingsin the dome 104 outward of the outer fuel nozzle opening 134 along theradial direction R are in airflow communication with the outer channel142 (with the potential exception of effusion cooling holes less thanabout 0.035 inches in diameter, as discussed above). Similarly, all theopenings in the dome 104 inward of the inner fuel nozzle opening 136along the radial direction R are in airflow communication with the innerchannel 144 (with the potential exception of effusion cooling holes lessthan about 0.035 inches in diameter, as discussed above). Notably,although at least certain of the plurality of outer openings 152 inairflow communication with the outer channel 142 are defined in the dome104 and in the outer vortex chamber wall 106 for the embodimentdepicted, in other exemplary embodiments, all of the plurality of outeropenings 152 in airflow communication with the outer channel 142 mayinstead be defined solely in the dome 104, or solely in the outer vortexchamber wall 106. Further, although at least certain of the plurality ofinner openings 180 in airflow communication with the inner channel 144are defined in the dome 104 and in the inner vortex chamber wall 108 forthe embodiment depicted, in other exemplary embodiments, all of theplurality of inner openings 180 in airflow communication with the innerchannel 144 may instead be defined solely in the dome 104, or solely inthe inner vortex chamber wall 108. Accordingly, as used herein, “all theopenings in the dome 104”, either outward of the outer fuel nozzleopening 134 or inward of the inner fuel nozzle opening 136, may refer tozero openings in the dome 104.

It should be appreciated, however, that in other exemplary embodiments,the trapped vortex combustor 100 may instead have any other suitableconfiguration. For example, in other exemplary embodiments of thepresent disclosure, the trapped vortex combustor 100 may not define boththe inner trapped vortex chamber 120 and outer trapped vortex chamber118. More specifically, in at least certain exemplary embodiments, thetrapped vortex combustor 100 may not define the inner trapped vortexchamber 120 and, instead, may only define outer trapped vortex chamber118. With such an exemplary embodiment, as discussed above, the outerfuel nozzle 138 may be positioned in an opening 134 in the dome 104, asshown, or alternatively may be positioned in an opening in the outertrapped vortex chamber wall 106.

Additionally, in still other exemplary embodiments, one or both of theinner channel 144 and outer channel 142 may have any other suitableconfiguration. For example, referring briefly to FIG. 6, a trappedvortex combustor 100 in accordance with another exemplary embodiment ofthe present disclosure is depicted. The exemplary trapped vortexcombustor 100 of FIG. 6 may be configured in substantially the samemanner as exemplary trapped vortex combustor 100 described above withFIGS. 2 through 5. For example, the exemplary trapped vortex combustor100 of FIG. 6 generally includes an outer vortex chamber wall 106, adome 104, and an inner vortex chamber wall 108. The dome 104 is attachedto, or rather formed integrally with, the outer vortex chamber wall 106to define at least in part an outer trapped vortex chamber 118 and anouter channel 142. Similarly, the dome 104 is attached to, or ratherformed integrally with, the inner vortex chamber wall 108 to define atleast in part an inner trapped vortex chamber 120 and an inner channel144. The dome 104 further defines an outer fuel nozzle opening 134 andan inner fuel nozzle opening 136, with all openings in the dome 104outward of the outer fuel nozzle opening 134 along the radial directionR being in airflow communication with the outer channel 142 and allopenings in the dome 104 inward of the inner fuel nozzle opening 136along the radial direction R being in airflow communication with theinner channel 144.

However, referring particularly to the inner channel 144 defined by oneor both of the dome 104 and the inner vortex chamber wall 108, the innerchannel 144 is split between an injection section 182 and a mixingsection 184. The plurality of openings in at least one of the dome 104and the inner vortex chamber wall 108 are in airflow communication withthe mixing section 184 of the inner channel 144 to provide asubstantially annular airflow to the injection section 182, such thatthe inner channel 144 may provide a more annular airflow to the innertrapped vortex chamber 120 during operation.

Notably, although only the inner channel 144 is configured with aseparate injection section 182 and mixing section 184, in otherexemplary embodiments, the outer channel 142 may additionally beconfigured in such a manner, or alternatively be configured in such amanner. Further, in still other embodiments, one or both of the outerchannel 142 or inner channel 144 may have any other suitable geometry.

Additionally, or alternatively, in still other exemplary embodiments,the trapped vortex combustor 100 may have any other suitableconfiguration. For example, instead of airflow flowing through outeropenings 152 defined in one or both of the dome 104 or the outer vortexchamber wall 106 to the outer channel 142, or through inner openings 180defined in one or both of the dome 104 or the inner vortex chamber wall108 to the inner channel 144, airflow may instead flow around one ormore these components. For example, referring now to FIG. 7, a close-up,cross-sectional view of an outer section of a trapped vortex combustor100 in accordance with another exemplary embodiment of the presentdisclosure is provided. The exemplary trapped vortex combustor 100 ofFIG. 7 may be configured in substantially the same manner as theexemplary trapped vortex combustor 100 described above with reference toFIGS. 1 through 5. For example, the exemplary trapped vortex combustor100 of FIG. 7 generally includes an outer vortex chamber wall 106 and adome 104, with the dome 104 attached to the outer vortex chamber wall106. Additionally, the outer vortex chamber wall 106 and the dome 104together define at least in part an outer trapped vortex chamber 118 andan outer channel 142.

However, for the embodiment of FIG. 7, neither the dome 104 nor theouter vortex chamber wall 106 define a plurality of outer openings 152(see above embodiments) in airflow communication with the outer channel142. Instead, the trapped vortex combustor 100 further includes a mount186, with the mount 186 defining a plurality of openings 188 in airflowcommunication with the outer channel 142. More particularly, for theembodiment depicted the outer vortex chamber wall 106 includes a wallflange 190 at a forward end 110 of the outer vortex chamber wall 106 andthe dome 104 includes a dome flange 192 at a radially outer end of thedome 104. The mount 186 includes a C-shaped flange 194 extending aroundthe wall flange 190 and the dome flange 192. The plurality of openings188 of the mount 186 are defined in a forward end of the C-shaped flange194 to provide an airflow around the dome 104 and outer vortex chamberwall 106 and to the outer channel 142 defined between the wall flange190 and dome flange 192. The outer channel 142 may then provide suchairflow as a continuous annular airflow to the inner surface 146 of theouter vortex chamber wall 106 during operation. It should beappreciated, however, that in other exemplary embodiments, air may flowthrough openings defined in one or more of the flange 194 of the mount186, the wall flange 190, and/or the dome flange 192. Such air may thenbe provided to the channel 142 defined by the outer vortex chamber wall106 and dome 104 (such components essentially forming a gaptherebetween).

Notably, referring still to FIG. 7, an attachment assembly 196 isprovided to attach the C-shaped flange 194 to the dome flange 192 andthe wall flange 190, connecting the dome 104 to the outer vortex chamberwall 106. More particularly, the attachment assembly 196 includes a bolt198, a nut 200, and a spacer 202. However, in other exemplaryembodiments any other suitable mount 186 and attachment assembly 196 maybe provided.

Furthermore, it will be appreciated that as with the other exemplaryembodiments described above, for the embodiment of FIG. 7, all openingsin the dome 104 outward of the outer fuel nozzle opening 134 along theradial direction R are in flow communication with the outer channel 142.More specifically, for the exemplary embodiment depicted, the dome 104does not include any openings outward of the outer fuel nozzle opening134 along the radial direction R.

Additionally, although not depicted, it should be appreciated that inother exemplary embodiments, the inner channel 144 may additionally, oralternatively, be configured in substantially the same manner asexemplary outer channel 142 described herein with reference to FIG. 7.

Referring now to FIG. 8, a flow diagram of a method 300 for operating atrapped vortex combustor of a gas turbine engine is provided. Thetrapped vortex combustor may be configured in a same or similar manneras one or more the exemplary trapped vortex combustors described abovewith reference to FIGS. 1 through 7. Accordingly, for example, thetrapped vortex combustor may include an outer vortex chamber wall and adome attached to, or formed integrally with, the outer vortex chamberwall. The dome, the outer vortex chamber wall, or both define at leastin part an outer trapped vortex chamber and a channel. The channel maybe positioned at a forward end of the outer vortex chamber wall.

The method 300 includes at (302) providing an airflow through or aroundthe dome, the outer vortex chamber wall, or both to the channel.Further, for the exemplary method 300 depicted, providing the airflowthrough or around the dome, the outer vortex chamber wall, or both tothe channel at (302) additionally includes at (304) providing theairflow through a plurality of airflow openings defined by the dome, theouter vortex chamber wall, or both.

Additionally the method 300 includes at (306) providing airflow througha plurality of airflow sources to the outer vortex chamber to provide atotal amount of airflow to the outer vortex chamber. More specifically,for the exemplary aspect depicted, providing airflow through theplurality of airflow sources to the outer vortex chamber at (306)includes at (308) providing the airflow received in the channel at (302)to the outer vortex chamber as an annular airflow, with the annularairflow being at least about fifteen percent of a total amount ofairflow provided to the outer vortex chamber.

Moreover, providing the airflow received in the channel at (302) to theouter vortex chamber as the annual airflow at (308) additionallyincludes at (310) providing the airflow received in the channel to theouter vortex chamber as an annular airflow along an inner surface of theouter vortex chamber wall.

Furthermore, for the exemplary aspect of FIG. 8, it will be appreciatedthat the channel is an outer channel, that the combustor furtherincludes an inner vortex chamber wall, with the dome being attached to,or formed integrally with the inner vortex chamber wall. Additionally,the dome, the inner vortex chamber wall, or both define at least in partan inner trapped vortex chamber and an inner channel positioned at aforward end of the inner vortex chamber wall.

Moreover, with such an exemplary aspect, the method 300 further includesat (312) providing an airflow through or around the dome, the innervortex chamber wall, or both to the inner channel. Further, for theexemplary method 300 depicted, providing the airflow through or aroundthe dome, the inner vortex chamber wall, or both to the channel at (312)additionally includes at (314) providing the airflow through a pluralityof inner airflow openings defined by the dome, the inner vortex chamberwall, or both.

Additionally the method 300 includes at (316) providing airflow througha plurality of airflow sources to the inner vortex chamber to provide atotal amount of airflow to the inner vortex chamber. More specifically,for the exemplary aspect depicted, providing airflow through theplurality of airflow sources to the inner vortex chamber at (316)includes at (318) providing the airflow received in the inner channel at(312) to the inner vortex chamber as an annular airflow, with theannular airflow being at least about fifteen percent of a total amountof airflow provided to the inner vortex chamber.

Moreover, providing the airflow received in the inner channel at (312)to the inner vortex chamber as the annual airflow at (318) additionallyincludes at (320) providing the airflow received in the inner channel tothe inner vortex chamber as an annular airflow along an inner surface ofthe inner vortex chamber wall.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A trapped vortex combustor for use in a gasturbine engine, the trapped vortex combustor defining a radial directionand a circumferential direction, the trapped vortex combustorcomprising: an outer vortex chamber wall defining a forward end andcomprising an inner surface; and a dome attached to, or formedintegrally with, the outer vortex chamber wall, the dome, the outervortex chamber wall, or both defining at least in part an outer trappedvortex chamber and a channel, the channel extending along thecircumferential direction at the forward end of the outer vortex chamberwall, the channel configured to receive an airflow through or around theouter vortex chamber wall, the dome, or both and provide such airflow asa continuous annular airflow to the inner surface of the outer vortexchamber wall, wherein the dome further defines a fuel nozzle opening,with all openings in the dome outward of the fuel nozzle opening alongthe radial direction, excepting any effusion cooling holes having adiameter less than about 0.035 inches, being in airflow communicationwith the channel.
 2. The trapped vortex combustor of claim 1, furthercomprising: an inner combustion chamber liner and an outer combustionchamber liner together defining a combustion chamber, wherein the outervortex chamber is positioned upstream of the combustion chamber.
 3. Thetrapped vortex combustor of claim 1, wherein the dome, the outer vortexchamber wall, or both define a plurality of openings in airflowcommunication with the channel for providing the airflow to the channel.4. The trapped vortex combustor of claim 3, wherein both the dome andthe outer vortex chamber wall define the plurality of openings.
 5. Thetrapped vortex combustor of claim 3, wherein the plurality of openingsare spaced along the circumferential direction.
 6. The trapped vortexcombustor of claim 1, wherein the outer vortex chamber is configured toreceive a total amount of airflow during operation, and wherein at leastabout fifteen percent of the total amount of airflow is provided throughthe channel.
 7. The trapped vortex combustor of claim 1, wherein thechannel extends substantially continuously three hundred and sixtydegrees about an axial centerline of the trapped vortex combustor. 8.The trapped vortex combustor of claim 1, wherein the dome comprises alip extending into the outer vortex chamber, wherein the lip defines thechannel with the inner surface of the outer vortex chamber wall.
 9. Thetrapped vortex combustor of claim 1, further comprising: a mount,wherein the dome comprises a dome flange, wherein the outer vortexchamber wall comprises a wall flange, wherein the mount attaches thedome flange to the wall flange, wherein the channel is defined betweenthe dome flange and the wall flange, and wherein at least one of themount, the dome flange, or the wall flange defines a plurality ofopenings in airflow communication with the channel for providing theairflow to the channel.
 10. The trapped vortex combustor of claim 1,wherein the channel is an outer channel, and wherein the combustorfurther comprises: an inner vortex chamber wall defining a forward endand comprising an inner surface, wherein the dome is attached to, orformed integrally with, the inner vortex chamber wall, wherein the dome,the inner vortex chamber wall, or both define at least in part an innertrapped vortex chamber and an inner channel, the inner channel extendingalong the circumferential direction at the forward end of the innervortex chamber wall, the inner channel configured to receive an airflowthrough or around the inner vortex chamber wall, the dome, or both andprovide such airflow as a continuous annular airflow to the innersurface of the inner vortex chamber wall.
 11. The trapped vortexcombustor of claim 10, wherein the fuel nozzle opening of the dome is anouter fuel nozzle opening, wherein the dome further defines an innerfuel nozzle opening, and wherein all openings in the dome inward of theinner fuel nozzle opening along the radial direction, excepting anyeffusion cooling holes having a diameter less than about 0.035 inches,are in airflow communication with the inner channel.
 12. The trappedvortex combustor of claim 10, wherein the inner channel extendssubstantially continuously three hundred and sixty degrees about anaxial centerline of the trapped vortex combustor.
 13. The trapped vortexcombustor of claim 1, wherein the channel is an outer channel definingan outlet, wherein the trapped vortex combustor further comprises: aninner vortex chamber wall defining a forward end, wherein the dome, theinner vortex chamber wall, or both define at least in part an innerchannel at the forward end, wherein the inner channel defines an outlet,wherein the trapped vortex combustor defines a cavity height between theouter vortex chamber wall at the outlet of the outer channel and theinner vortex chamber wall at the outlet of the inner channel, whereinthe outer channel further defines a maximum height, and wherein themaximum height of the outer channel is between about 0.1 percent andabout eight percent of the cavity height.
 14. The trapped vortexcombustor of claim 1, wherein the channel is an outer channel definingan outlet, wherein the trapped vortex combustor further comprises: aninner vortex chamber wall defining a forward end, wherein the dome, theinner vortex chamber wall, or both define at least in part an innerchannel at the forward end, wherein the inner channel defines an outlet,wherein the trapped vortex combustor defines a cavity height between theouter vortex chamber wall at the outlet of the outer channel and theinner vortex chamber wall at the outlet of the inner channel, whereinthe fuel nozzle opening defines a separation from the inner surface ofthe outer vortex chamber wall, and wherein the separation is betweenabout one percent and about eight percent of the cavity height.
 15. Atrapped vortex combustor for use in a gas turbine engine, the trappedvortex combustor defining a radial direction and a circumferentialdirection, the trapped vortex combustor comprising: an outer vortexchamber wall defining a forward end and comprising an inner surface; anda dome attached to, or formed integrally with, the outer vortex chamberwall, the dome, the outer vortex chamber wall, or both defining at leastin part an outer trapped vortex chamber and a channel, the channelextending along the circumferential direction at the forward end of theouter vortex chamber wall, the channel configured to receive an airflowthrough or around the outer vortex chamber wall, the dome, or both andprovide such airflow as a continuous annular airflow to the innersurface of the outer vortex chamber wall, wherein the outer vortexchamber is configured to receive a total amount of airflow duringoperation, and wherein at least about fifteen percent of the totalamount of airflow is provided through the channel.
 16. A method foroperating a trapped vortex combustor of a gas turbine engine, thetrapped vortex combustor comprising an outer vortex chamber wall and adome attached to, or formed integrally with, the outer vortex chamberwall, the dome, the outer vortex chamber wall, or both defining at leastin part an outer trapped vortex chamber and a channel, the channelpositioned at a forward end of the outer vortex chamber wall, the methodcomprising: providing an airflow through or around the dome, the outervortex chamber wall, or both to the channel; and providing the airflowreceived in the channel to the outer vortex chamber as an annularairflow, the annual airflow being at least about fifteen percent of atotal amount of airflow provided to the outer vortex chamber.
 17. Themethod of claim 16, wherein the annual airflow is between about twentypercent and about forty percent of the total amount of airflow providedto the outer vortex chamber.
 18. The method of claim 16, whereinproviding the airflow through or around the dome, the outer vortexchamber wall, or both to the channel comprises providing the airflowthrough a plurality of airflow openings defined by the dome, the outervortex chamber wall, or both.
 19. The method of claim 16, whereinproviding the airflow received in the channel to the outer vortexchamber as an annual airflow comprises providing the airflow received inthe channel to the outer vortex chamber as an annular airflow along aninner surface of the outer vortex chamber wall.
 20. The method of claim16, wherein the channel is an outer channel, wherein the combustorfurther comprises an inner vortex chamber wall, wherein the dome isattached to, or formed integrally with, the inner vortex chamber wall,wherein the dome, the inner vortex chamber wall, or both define at leastin part an inner trapped vortex chamber and an inner channel positionedat a forward end of the inner vortex chamber wall, wherein the methodfurther comprises: providing an airflow through or around the dome, theinner vortex chamber wall, or both to the inner channel; and providingthe airflow received in the inner channel to the inner vortex chamber asan annual airflow, the annual airflow being at least about fifteenpercent of a total amount of airflow provided to the inner vortexchamber.